Stellar class format

[ajtribick]

The format of the stellar class field in the stars.dat file is a 2-byte integer consisting of four groups of four bits.

The meaning of the four groups (3210) is given at http://members.fortunecity.com/guilpain/Stars_uk.htm as:

3 - star class: 0 = normal, 1 = white dwarf, 2 = neutron star, 3 = black hole (although neutron stars and black holes do not appear in the default stars.dat)

2 - spectral class (0=O through BAFGKMRS to N=9, WC=10, WN=11)

1 - subtype (0 through 9)

0 - luminosity class (0=Ia-0 through Ia II III IV V VI=7)

Groups 2, 1 and 0 do not appear to have any use if group 3 is set to zero.

However since that page was put up Celestia now supports more spectral types (L and T for brown dwarfs, and apparently the latest prerelease supports C type carbon stars as well)

Is it possible to specify these spectral types in stars.dat and if so, what numbers are they?

Also does the prerelease support white dwarf subtypes?

[granthutchison]

The current spectral class coding is as follows:
0 – O
1 – B
2 – A
3 – F
4 – G
5 – K
6 – M
7 – R
8 – S
9 – N
10 – WC
11 – WN
12 – unknown
13 – L
14 – T
15 – C

There's no support for WD classes yet, but that should be coming.

Grant

[ajtribick]

Thanks